Integral curvature bounds and diameter estimates on Finsler manifolds

In this paper, we study the integrals of the Ricci curvature over metric balls in a Finsler manifold,which can be viewed as an L~q-norm of the Ricci curvature. By bounding such integrals from above, we obtain several Myers type theorems.     

人造麝香的危害性及其残留检测方法研究进展

综述了近年来人造麝香的危害性及其残留检测方法的研究进展。对化妆品、水、大气、土壤和药物中人造麝香的前处理方法和检测方法进行了比较,同时对此领域的发展方向进行了展望(引用文献31篇)。     

Efficient method for the synthesis of polysubstituted 2,6-dicyanoanilines by one-pot three-component tandem reaction of malononitrile with <Emphasis Type="Italic">α</Emphasis>,<Emphasis Type="Italic">β</Emphasis>-unsaturated imines

A facile and efficient one-pot synthesis of polysubstituted benzenes was achieved via the Michael addition of malononitrile with α,β-unsaturated imines and a sequential tandem reaction. This reaction generates polysubstituted 2,6-dicyanoanilines in high yields (15 examples, isolated yields of 57–91 %), and proceeds under mild reaction conditions (60°C, 10 min). In addition, a possible mechanism accounting for the reaction is proposed.     

Thermo- and pH-responsive fluorescence behaviors of sulfur-functionalized detonation nanodiamond-poly(<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide)

Detonation nanodiamonds (DNDs) are emerging as bioimaging platforms due to their biocompability, small primary particle size, reactive surface, and stable fluorescence after modification. In this paper, a heteroatom engineering method is provided to fabricate the fluorescent DNDs through pyrolysis of dibenzyl disulfide. The quantum yield of these sulfur (S)-functionalized DNDs (SDNDs) increases with sulfur percentage. The solubility and stability of SDNDs in aqueous solution are also significantly increased due to the formation of hydrophilic sulfur groups on DND. Furthermore, these SDNDs are used to conjugate the stimuli-responsive poly(N-isopropylacrylamide) (PNIPAM) through the ‘graft from’ method. The conjugation demonstrated both pH- and thermo-responsive fluorescence behaviors, which shows promise to be used in ratiometric fluorescence sensing for the detection of intracellular pH and temperature values.     

Strand displacement amplification for ultrasensitive detection of human pluripotent stem cells

Human pluripotent stem cells (hPSCs), such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), provide a powerful model system for studies of cellular identity and early mammalian development, which hold great promise for regenerative medicine. It is necessary to develop a convenient method to discriminate hPSCs from other cells in clinics and basic research. Herein, a simple and reliable biosensor for stem cell detection was established. In this biosensor system, stage-specific embryonic antigen-3 (SSEA-3) and stage-specific embryonic antigen-4 (SSEA-4) were used to mark human pluripotent stem cells (hPSCs). Antibody specific for SSEA-3 was coated onto magnetic beads for hPSCs enrichment, and antibody specific for SSEA-4 was conjugated with carboxyl-modified tDNA sequence which was used as template for strand displacement amplification (SDA). The amplified single strand DNA (ssDNA) was detected with a lateral flow biosensor (LFB). This biosensor is capable of detecting a minimum of 19 human embryonic stem cells by a strip reader and 100 human embryonic stem cells by the naked eye within 80 min. This approach has also shown excellent specificity to distinguish hPSCs from other types of cells, showing that it is promising for specific and handy detection of human pluripotent stem cells.